Thimble removal press



J. w. TOMKA 3,062,425

THIMBLE REMOVABLE PRESS Nov. 6, 1962 Filed Aug. 26. 1958 4 Sheets-Sheet1 IN V EN TOR.

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Nov. e, 1962 J w. TOM@ 3,o62,425

THIMBLE REMOVABLE PRESS Filed Aug. 26, 1958 4 Sheets-Sheet 5 IN V ENTUR.

4 Sheets-Sheet 4 Filed Aug. 26. 1958 Unted States Parent Q 3,062,425THIMBLE REMOVAL PRESS I Joseph W. Tomka, Cincinnati, Ohio, assignor, bymasne assignments, to Nordberg Manufacturing Company, a corporation ofWisconsin Filed Aug. 26, 1958, Ser. No. 757,353 7 Claims. (Ci. 225-403)This invention relates to a device for removing frangible rings from abar and particularly to a device for removing cast iron thimbles fromanode bars utilized in the rening of aluminum.

The method most commonly utilized to produce commercially pure aluminumis to place a charge of refined ore called alumina in a carbon pot. Acarbon block preferably comprising petroleum coke, pitch, and anthraciteblended together and formed under pressure is lowered into the pot. Anelectrical current is passed through the block, which acts as the anode,and the pot, which acts as the cathode, whereupon the aluminum is meltedout of the alumina ore and siphoned oit'. During the refining process,the carbon block burns down and must be replaced on the support bar onwhich it is carried.

The support bars are transported through the various Operating stationsby a conventional overhead conveyor system. The preformed carbon blocksare provided with a cored cavity arranged to receive a steel stubcarried by the copper support bars. The block is bonded to the steelstub by pourng molten iron into the cavity surrounding the stubwhereupon the iron hardens and firmly anchors the block to the stub.After the carbon block has been burned down, it is necessary that thesmall remaining portion of the block and the cast iron thimble, whichanchored the block to the stub, be removed from the bar. In the past,the removal of the cast iron thimble has been done almost completelymanually and the job was diflicult, time consuming, and costly.

It is, therefore, a primary object of the present invention to provide adevice for stripping such an iron thimble from the support bar stub in afast, efficient, and inexpensive manner.

A further object of the invention is to provide an arrangement forremoving such cast iron thimbles from the steel stubs of a support bar,without removing the bar from its overhead conveyor, by press means forforcing the stub and block against wedge type strippers which act tofracture the thimble and thereby cause its effective removal from thebar stub.

The invention is best illustrated with reference to the accompanyingdrawings Wherein:

FIGURE 1 is a front elevational view, partly in section, of thepreferred embodiment of the thimble removing press;

FIGURE 2 is a side elevational view, partially in seetion, of thestructure of FIGURE 1;

FIGURE 3 is a top plan view of the structure of FIG- URE l;

FIGURE 4 is a fragmentary vertical sectional view of the stripper puncharrangement;

FIGURE 5 is a fragmentary side view of the stripper punch and,

FIGURE 6 is a schematic valve and piping layout for the arrangement.

Referring to the drawings and particularly to FIG- URES 1 and 2, it isseen that a support bar, indicated generally at 10, is carried by aconventional overhead conveyor arrangement 12. The conveyor is formed ofan I-beam 14 arranged to support an anode bar body 16 through rollers18. The moving force is supplied to the foregoing assembly by means of adrive conveyor, generally indicated at 20, which similarly is formed ofan I-beam 22 arranged to support a plurality of spaced mernbers 24 bymeans of rollers 26. The spaced members 24 are secured to and driven bya chain (not shown) and drives the anode bar 16 through a drive rod 28which is secured to the support bar 10.

In the preferred form, each anode bar 16 is arranged to support a pairof carbon blocks. Obviously, however, each anode bar could be utilizedto support a single carbon block. Referrng to FIGURE 2, it is seen thata cross bar 30 is secured to the bar 16. The ends of the cross bar 30are turned down as at 31 and a steel stub 32 is bonded to each of theturned down portions. A schematic cast iron thimble is indicated at 36in FIGURES 1 and 2 and the contour of the thimble, best seen in FIG-URES 4 and S, corresponds to the contour of the cored opening in thecarbon block. The fragmentary burned down carbon block 41 is illustratedin only certain of the views because the primary concern of theinvention is the removal of the cast iron thimble from the stub, and thecarbon block fragment is removed simultaneously with the thimble.

The present invention contemplates the use of a press for removing thecast iron thimbles and is best illustrated in FIGURES 1 through 3. Thepress, indicated generally at 38, comprises a base 40 on which aremounted spaced housings 42, the assembly being held together by means ofconventional tie bolts 43. Each anode bar is conveyed to the pressstation in a manner which will be explained hereinafter. After arrivingat the press Stations, the anode bar is held in position and preventedfrom rotating by means of an ensnaring bar 44 (FIGURE 3) which issupported for horizontal movement in spaced guides 46. The ensnaring bar44 is secured to the piston rod 48 of an air cylinder 50 which, Whenactivated, moves the ensnaring bar 44 to a position whereat the body 16of the anode bar is received in the U-shaped opening 51.

After the bar has been properly positioned, opposed stripper jaws 52 aremoved into position by means of stripper jaw cylinders 54 so that thesemi-cylindrical openings 56 surround, but do not contact the steelstubs 32. As seen in FIGURE 1, the stripper jaws 52 move into positionadjacent the upper surface of each thimble in order to restrain thethimble from upward movement during its removal from the steel stub.

The base 40 of the press 38 is provided with an hydraulic cylinder 60which carries a ram 62 to the end of which is secured one or morestripper punches 64. The stripper punch is best illustrated in FIGURES 4and 5. The punch at its extreme end 66 has a diameter which is less thanthe internal diameter of the cast iron thimble and diverges outwardlytherefrom to form wedge surfaces 68. The wedge surfaces 68 may beprovided at circumferentially spaced points on the punch, but preferablyare formed as a single frustro-conical surface around the punch, and areformed so that their widest dimension eX- ceeds the internal diameter ofthe cast iron thimble. The punch may also be provided with breakerpoints 70, preferably in the form of a single rod extending through thepunch and extending outwardly of the wedge surfaces, as best seen inFIGURE 4. The breaker points 70 are provided with knife edges 72 for apurpose to be described hereinafter.

Referring specifically to FIGURE 4, it is seen that as the punch 64moves upwardly, the punch end 66 contacts the lower surface of the steelstub 32 and moves the stub upwardly out of the cast iron thimble whichis restraned from movement by the stripper jaws 52. As the punchcontinues its upward movement, the wedge surfaces 68 thereof contact thejuncture of the lower surface of the thimble and the inner peripherythereof and by wedging action tend to expand the thimble. The thimble,however, being frangible, shatters and drops away from the steel stub32. The advantages of this type of removal are that a shorter pressstroke may be utilized than would be required if the stub were forcedcompletely out of the thimble and, furthermore, the cast iron thimbleimmediately drops completely away from the stub and the punch ratherthan being received around the punch which would be the case if thethimble were not broken. In the latter instance, a separate operationwould be necessa'y to remove the thimble from around the punch.

The shattered thimble is preferably dropped into one or more chutes (notshown) down which it slides into scrap boxes. It is, therefore,desirable to force the thimble to break in a preferred manner so thatthe thimble pieces will fall according to a predetermined pattern. Thisis accomplished by means of the breaker points 70. Referring to FIGURE4, it is seen that, as the punch moves upwardly, the knife edges 72 arearranged to contact the bottom surface of the cast iron thimble atapproximately the same time that the thimble is contacted by the wedgesurfaces. The knife edges 72, therefore, exert a pressure on the thimblewhich causes the thimble to shatter in an axial plane substantiallyaligned with the breaker points. The discharge chutes can, therefore, bearranged in the most convenient position with assurance that the piecesof the broken thimble Will always fall into the chutes rather than intosome other parts of the press. As explained heretofore, the thimble isheld stationary during a stripping operation while the punch forces thesteel stub, and with it the entire support bar 10, in an upwarddirection. To accommodate this movement, the fixed eonveyor 12 isprovided with a movable portion 82 (FIGURE 2) which is free to moveupwardly with the support bar.

A counter-balance, shown generally at 80, is also provided to otfsetmost of the weight of the eonveyor portion 82 and of the support barassembly so that its entire weight need not be carried by the punch andthe punch actuating ram. The counterbalance arrangement is best shown inFIGURE 2. It comprises a frame portion 84, rigidly Secured to the fixedeonveyor rail 14. A counterbalance cylinder 86 is carried by the franeand is provided with a cylinder rod 83 which in turn supports a guideassembly 88 arranged to ride in tracks 90 provided on the frame 84. Themovable conveyor portion is in turn supported by the guide assembly.During a stripping operation the cylinder 86 is actuated and is adjustedto provide an upward force which is just slightly less than the combinedweight of the guide assembly, movable conveyor portion and support barassembly. Thus, the stripper cylinder 60 need turnish only enough forceto strip the thimble from the steel stub and can thus be made smallerthan if it were required to support all of the structure above the stub.

The cycle of operation will be best understood with reference to theschematic diagram illustrated in FIG- URE 6. When the support barcarrying one or more thimbles to be removed is fed into the pressstation, a limit switch (not shown) is tripped to energize a controlrelay (not shown). Energization of the relay energizes a solenoid 100whereby the spool of valve 102 is shifted to accomm'odate flow of shopair from port Q of valve 102 to port S and thence to the head end of aircylinder 86 whereby a counterbalancing force is provided as explainedheretofore. Simultaneously with the energization of solenoid 100,solenoid 110 is energized to shift the spindle of valve 112 to supplyair to the head end of ensnaring cylinder 50 which moves the ensnaringbar (FIGURE 3) into position to prevent further motion of the supportbar 10. When the ensnaring bar has reached its extreme position, limitswitch 114 is tripped to complete a circuit to energize solenoid 116 ofpressure compensating pump 118. Oil is now pumped through line 119 tothe head ends of the four stripper jaw cylinders 54 which move thestripper jaws into position immediately adjacent the upper surfaces ofthe related thimbles and surrounding, but not contacting, the relatedsteel stubs. Each of the stripper jaws, when reaching its properposition, trips an associated limit switch. These switches aredesignated 120, 122, 124, and 126. When all four limit switches havebeen tripped, a relay (not shown) is energized to complete a circuit tosolenoid 132 of pressure compensating pump 134 whereby oil fiows throughline 135 into the head end of the stripper cylinder 60. The ram 62,together with the punch 64, now moves upwardly as described heretoforeto perform the stripping operation.

In certain instances sufficient tonnage may not be attained by the ram62 to strip a thimble from the stub. To alleviate this situation, apressure switch 136 is provided which is set at the maximum pressure ofthe pump 134 and which will trip when this pressure is reached in orderto allow the ram 62 to return to its lowered position and, therefore,not stop the press cycle. In these instances, of course, the thimbleshave to be removed by hand.

After the ram 62 has completed its stripping operation, it travels untillimit switch 138 is tripped causing solenoid 116 to be de-energized andsolenoid 140 to be energized. Oil now flows through line 142 into therod ends of the four stripper jaw cylinders 54 and the stripper jaws areconsequently moved away from the support bar assembly. Simultaneously,solenoid 132 of pump 134 is de-energized and solenoid 148 is energized.Oil now flows through line 150 and check valve 151 to the rod end of thecylinder 60 whereupon the ram 62 moves downwardly. At the same time, apilot line 152 Supplies oil pressure to the spindle of by-pass valve 154to Shift the valve to open position. Part of the oil, therefore, fromthe head end of cylinder 60, is forced out of the cylinder through line150 and back to the reservoir 156 while the excess oil travels throughby-pass valve 154 to the reservoir 156. When the ram 62 reaches itslowest position, limit switch 160 is tripped to de-energize solenoid 148of pump 134 to neutralize the pressure in the lines leading from thispump.

When all four of the stripper jaw rams have completed their returnstroke, pressure builds up at the rod end of the cylinders 54 until thepressure setting of switch 162 is reached. The switch 162 is therebytripped and a circuit is completed to de-energize solenoid 140 of pump118 to neutralize the pressure in this pump. Simultaneously, solenoids100 and 110 are de-energized. Deenergizing solenoid 100 reverses the ramof cylinder 86 to relieve the pressure in the counterbalancearrangement. De-energizing solenoid 110 reverses the ram of cylinder 50whereupon the ensnaring bar 48 is moved to its retracted position. Atthis time, a limit switch 166 is tripped indicating the end of the cyclewhereupon the eonveyor mechanism 20 feeds the support bar out of thepress and moves another support bar into the press to cause the cycle tobe repeated.

I claim:

1. In an arrangement for removing a frangible thimble from a supportbar, the combination of: means for restraining axial movement of thethimble; a punch aligned with the support bar nad movable axiallythereof, said punch having Wedge surfaces engageable with the thimblefor eXer-ting a wedgng force against a portion of the internal peripheryof the thimble to break the latter upon aXial movement of the punch; andbreaker means on said punch extending radially thereof and engageablewith the end of the thimble adjacent the punch for exerting pressure atspaced points on said end and thereby controlling the manner of breakingof said thimble.

2. In an arrangement for removing a frangible, generally cylindrical,ring from a support bar, the combination of: stripper jaw means forrestraining axial movement of said ring while accommodating axialmovement of said support bar; a punch axially aligned with the supportbar and engageable therewith; power means to impart axial movement tothe punch; said punch having an end diameter smaller than the internaldiameter of the ring, said punch having wedge surfaces divergingoutwardly from said punch end and engageable with the inner periphery ofthe ring to break the latter by wedging action; and breaker means onsaid punch engageable with the end of the ring adjacent the punch forcontrolling the manner of breaking of said ring.

3. In an hydraulic press arrangement for removing a cast iron ring froma support bar, the combination of: a conveyor rail; a support barcarried by said rail and movable along a path to a press station; a pairof jaws movable to a position substantially surrounding the support barand adjacent the upper surface of said ring; a stripper punch aXiallyaligned With said support bar and engageable with the bottom surfacethereof; power means to move said punch to urge said support barupwardly and out of said ring; wedge surfaces on said punch engageablewith the juncture of the inner periphery and the lower surface of saidring whereby said ring is broken as said punch and support bar moveupwardly; a portion of said conveyor rail being movable upwardly toaccommodate the movement of said support bar.

4. In an hydraulic press arrangement for removing a cast iron ring froma support bar, the combination of: a conveyor rail; a support barcarried by said rail and movable along a path to a press station; a pairof jaws movable to a position substantially surrounding the support barand adjacent the upper surface of said ring; a stripper punch axiallyaligned with said support bar and engageable with the bottom surfacethereof; power means to move said punch to urge said support barupwardly and out of said ring; wedge surfaces on said punch engageablewith the juncture of the inner periphery and the lower surface of saidring whereby said ring is broken as said punch and support bar moveupwardly; a portion of said conveyor rail being movable upwardly toaccommodate the movement of said support bar; and knife edge means onsaid punch engageable with the lower surface of said ring for exertingpressure at spaced points thereof for causing the ring to break in apredetermined manner.

5. In an hydraulic pressure arrangement for removing a cast iron ringfrom a support bar, the combination of: a conveyor rail; a support barcarried by said rail and movable along a path to a press station; a pairof jaws movable to a position substantially surrounding the support barand adjacent the upper surface of said ring; a stripper punch axiallyaligned With said support bar and engageable with the bottom surfacethereof; power means to move said punch to urge said support barupwardly and out of said ring; wedge surfaces on said punch engageablewith the juncture of the inner periphery and the lower surface of saidring whereby said ring is broken as said punch and support bar moveupwardly to accommodate the movement of said support bar; andcounterbalance means operatively connected to said support bar urgingsaid support bar upwardly with a force slightly less than the combinedweight of the support bar and ring.

6. In an arrangement for removing a frangible ring from a supportmember; stripper means for moving said ring and member relatively ofeach other in an axial direction; wedge means movable with the strippermeans and engageable with a portion of the inner perphery of said ringfor breaking the latter into at least two separable pieces; and aplurality of substantially knife edge means engageable with the ring atspaced points for controlling the manner of breaking of the ring.

7. In an arrangement for removing a frangible ring from a supportmember, stripper means for moving said ring and member relatively toeach other in an axial direction, wedge means movable relative to saidstripper means and engageable with at least a portion of the innerperiphery of said ring causing said portion to move in a direction awayfrom said support member, and breaker means associated with said wedgemeans and engageable With said ring for controlling the manner ofbreaking of said ring, said breaker means comprsing an elongated bodyportion insertable into said wedge in a manner so as to have at leastone end of said body portion extending beyond the surface of said wedgemeans, and a knife-like surface formed on said breaker means bodyportion for at times engaging said ring.

References Cited in the file of this patent UNITED STATES PATENTS530,866 Vanhouten Dec. 11, 1894 749,369 Durkee Jan. 12, 1904 1,276,278Smallwood Aug. 20, 1918 1,366,693 Kemble Jan. 25, 1921 1,622,029 DovelMar. 22, 1927 1,630,759 Pierce May 31, 1927 2,334,940 LeTourneau Nov.23, 1943 2,654,310 Muller Oct. 6, 1953 2,707,324 Walther May 3, 19552,722,174 Albers Nov. 1, 1955 2,740,474 Harrison Apr. 3, 1956 FOREIGNPATENTS 221,093 Great Britain Sept. 4, 1924

